#include<stdio.h>

int main()
{
    int n, m = 0, fac = 1;
    scanf("%d", &n);
    double sum = 0;
    while(sum < n)
    {
        m ++;
        fac *= m;
        sum += fac;
        
    }
    printf("m<=%d", m - 1);
    return 0;
}